Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Musculoskeletal System > 9. Cartilage of the Joint > Flashcards

9. Cartilage of the Joint Flashcards

1
Q

what is CARTILAGE

A

specialized form of CONNECTIVE TISSUE that consists of CELLS and
EXTRACELLULAR MATERIAL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do you find in CARTILAGE, EMBEDDED in ECM

A

CHONDROCYTES
- secrete extracellular material (mostly matrix proteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what gives the cartilage its unique characteristics

A

MATRIX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

CARTILAGES are classified into: (3)

A
  • HYALINE CARTILAGE
    (mainly in Synovial Joints)
  • ELASTIC CARTILAGE
    (outer ear, larynx, epiglottis)
  • FIBROCARTILAGE
    weight-bearing
    (pubic symphysis, intervertebral discs, meniscus, and temporomandibular joint)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what do you find in ELASTIC CARTILAGE (in matrix)

A

ELASTIC FIBRES in matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what do you find in the MATRIX of FIBROUS CARTILAGE

A

COLLAGEN FIBRES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

COMPONENTS of CARTILAGE (3)

A

COLLAGEN
ELASTIN
PROTEOGLYCAN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which COLLAGEN is the main one in CARTILAGE

A

TYPE 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

PURPOSE of COLLAGEN in CARTILAGE

A

provide structural STRENGTH

  • therefore type 2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

PURPOSE of ELASTIN in CARTILAGE

A

FLEXIBILITY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

PURPOSE of PROTEOGLYCAN in CARTILAGE

A

provides LARGE OSMOTIC EFFECT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how do PROTEOGLYCANS in CARTILAGE provide LARGE OSMOTIC EFFECT

A
  • they carry many NEGATIVE CHARGES
  • ATTRACT CATIONS (+) eg Na2+ SODIUM
  • resulting in LARGE OSMOTIC EFFECT which HOLDS WATER in the MATRIX (flow of water from the weak solution to the strong solution - WATER IN, enhances ability to BEAR LOAD)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a PROTEOGLYCAN

A
  • PROTEOGLYCANS consist of a core protein with at least one GLYCOSAMINOGLYCAN (GAG) COVALENTLY LINKED

Glycosaminoglycan: long
unbranched polysaccharide chains composed of repeating disaccharide units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

EXAMPLE of a major PROTEOGLYCAN in CARTILAGE

A

AGGRECAN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what joint related substance is a NONSULFATED GLYCOSAMINOGLYCAN

A

HYALURONIC ACID

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the MAIN FUNCTION of CARTILAGE

A

CONNECT BONES TOGETHER

(also found in the joints, the rib-cage, the ear, the nose, the throat and between the bones of the back)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

another FUNCTION of CARTILAGE

A

create a place on which BONES CAN FORM when they are first developed
- growth plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

structure of the ECM of ELASTIC CARTILAGE

A

CRISS-CROSSED by numerous BRANCHED ELASTIC FIBRES - rich in ELASTIN (protein)

(see image)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ELASTIC FIBRES in ELASTIC CARTILAGE have a HIGH DEGREE OF FLEXIBILITY and RESILIENCE.
what % of their orginial length:

A

150% of ORIGINAL LENGTH

When bent, elastic cartilage will rapidly bounce back to its original form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what do you find on the OUTER MARGINS of ELASTIC CARTILAGE

A

fibrous PERICHONDRIUM

  • made of dense connective tissue (collagen secreted by FIBROBLASTS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

where is ELASTIC CARTILAGE MAINLY FOUND (3)

A
  • EXTERNAL EAR
  • EUSTACHIAN TUBES (opening that connects the middle ear with the nasal-sinus cavity)
  • epiglottis (flap of tissue that sits beneath the tongue at the back of the throat)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does FIBROCARTILAGE compose of

A

TYPE I COLLAGEN
& FIBROUS TISSUE

viewed as a composite/mixture of HYALINE CARTILAGE
and DENSE FIBROUS CONNECTIVE TISSUE (COLLAGEN I)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does FIBROCARTILAGE LACK

A

a true PERICHONDRIUM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

FUNCTION of FIBROCARTILAGE
what sort of sites is it found at

A

WEIGHT-BEARING

at sites which are subjected to TENSILE and COMPRESSIVE FORCES

forms a structural and functional junction
where cartilage and ligament meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

where is FIBROCARTILAGE FOUND

A

INTERVERTEBRAL DISCS

MENISCI of KNEE (Lateral & Medial)

TEMPOROMANDIBULAR JOINT

26
Q

ARTICULAR CARTILAGE is which type of cartilage

A

HYALINE

27
Q

2 FUNCTIONS of HYALINE CARTILAGE

A
  • DISTRIBUTE LOAD
    (shock absorb)
  • ALLOW MOVEMENT
28
Q

in HYALINE CARTILAGE, COLLAGEN TYPE II is ATTACHED to COLLAGEN TYPES..

A

9 IX
& 11 XI

29
Q

MATURE CHONDOCYTES (in hyaline and elastic cartilage) occupy spaces in the MATRIX called

A

LACUNA

30
Q

2 CHARACTERISTICS of ARTICULAR CARTILAGE

A

AVASCULAR (no blood supply)

ANEURAL (no nerves)

31
Q

ARTICULAR CARTILAGE is..

A

SHOCK-ABSORBING

32
Q

cells in the matrix of ARTICULAR CARTILAGE and what do they do

A

CHONDROCYTES
maintain a stable phenotype to retain their function as a permanent cartilage

33
Q

how are COLLAGEN FIBRES at SUPERFICICAL LAYER of ARTICULAR CARTILAGE vs DEEP LAYER

A

PARALLEL superficially

STOOD ON THEIR ENDS at DEEP layer
- collagen fibres most RESISTANT here

34
Q

ARTICULAR CARTILAGE has DIFFERENT ZONES
what does the TIDE MARK separate

A

CALCIFIED CARTILAGE (ZONE 4)

(zones 1-3: Tangenital, Transitional, Radial)

35
Q

PROTEOGLYCANS/AGGRECAN occupy LARGE VOLUME of WATER (due to NEGATIVE charge due to GLYCOSAMINOGLYCAN CHAINS attached).

this brings about a RISE IN OSMOTIC PRESSURE and SWELLING of cartilage.

HOW IS THIS HELD TOGETHER WHEN LOAD IS APPLIED?

A

RESISTANCE of COLLAGEN (intact collagen fibres) in cartilage
COUNTERACTS SWELLING PRESURE and holds cartilage intact.

these features enable joints to RESIST COMPRESSIVE FORCE while MAINTAINING a HIGH TENSILE STRENGTH

36
Q

SYNOVIAL FLUID is important for articular cartilage function.
what are its CHARACTERISTICS (4)

A

PLASMA-LIKE

LUBRICATION
to REDUCE FRICTION

supplies NUTRITION (as no bloody supply)

37
Q

COMPONENTS of SYNOVIAL FLUID

A
  • LUBRICIN - PROTEOGLYCAN
  • HYALURONAN, HA (hyaluronica acid) - GLYCOSAMINOGLYCAN
    (composed of the repeating sugars glucuronic acid & N-acetylglucosamine.)
  • PHOSPOLIPIDS
    eg Phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin
38
Q

LUBRICIN in SYNOVIAL FLUID (secreted by articular cartilage and synovium) is encoded by which GENE

A

PRG4

39
Q

FUNCTION of HA in SYNOVIAL FLUID

A

PROVIDES VISCOSITY to synovial fluid
(role in LUBRICATION)

through its high molecular weight (0.5–3.8 106 Da) and concentration (0.1– 5mg/mL).

40
Q

what do the PHOSPHOLIPIDS in SYNOVIAL FLUID provide

A

HYDROPHOBICITY to articular surface

& lubrication for solid-solid contact

41
Q

what is VISCOSITY a measure of

A

INTERNAL FRICTION of a FLUID

42
Q

What is SHEAR

A

the GREATER the FRICTION

a strain produced by pressure in the structure of a substance

the GREATER the FORCE NEEDED

43
Q

VISCOSITY formula
VISCOSITY =

A

SHEAR STRESS / SHEAR RATE

SHEAR RATE: the measure of the FLUID SPEED compared to the SURFACE that its sliding from

44
Q

SHEAR THINNING is derived from…as…

A

HA ALLIGNMENT MOLECULE
as the SHEER RATE INCREASES

movement of the alignment as as you move the joint

45
Q

MODELS of LUBRICATION in ARTICULAR CARTILAGE:
1. SQUEEZE FILM:

A

as 2 surfaces are squeezed together,
FLUID is SQUEEZED OUT from the gap

generating a HYDROSTATIC PRESSURE

46
Q

MODELS of LUBRICATION in ARTICULAR CARTILAGE:
2. BOOSTING/BOOSTED

A

eg if jumping

WATER moves INTO cartilage and so
INCREASES CONCENTRATION of HYALURONIC ACID in fluid-film

47
Q

MODELS of LUBRICATION in ARTICULAR CARTILAGE:
3. ELASTOHYDRODYNAMIC

A

sliding MOVEMENT

DEFORMATION of the surface serves to
TRAP PRESSURIZED FLUID in 1 AREA

48
Q

FLUID-FILM MECHANISMS

A

NO CONTACT between surfaces,
FRICTION DEPENDENT on the VISCOSITY of the Lubricant

PROVIDE the LOW FRICTION ENVIRONMENT for the
articular cartilage at physiologic loads, accomplished by creating a wedge of fluid between the two bearing surfaces.
The most desirable lubrication

49
Q

BOUNDARY LUBRICATION

A

CHEMICAL PROPERTIES of Lubricant are NOT AS IMPORTANT as the SURFACES IN CONTACT

PREVENTS ASHESION and ABRASIONS of two surface

and is independent of the physical properties of the lubricant or contacting surfaces.

Hyaluronan and lubricin are believed to be the main boundary lubricants of the diarthrodial joint.

50
Q

what is the LAMBDA RATIO a measure of

A

MINIMUM FILM THICKNESS (h min) required
in relation to the composite surface ROUGHNESS (Ra1, Ra2)

shown on STIBECK CURVE
friction coefficient against the bearing number μω/p (lubricant viscosity (η), speed (ω) and contact pressure (p) )

COEFFICIENT OF FRICTION is DIRECTLY PROPORTION to the VISCOSITY of the lubricant and the DIFFERENCE IN SPEED of the contact surfaces;

and INVERSELY PROPORTIONAL to the PRESSURE which is EXERTED on the contact SURFACES

*Boundary lubrication: λ ≤ 1
*Mixed lubrication: 1 < λ < 3
*Fluid film lubrication: λ ≥ 3

51
Q

3 types of WEAR of articular cartilage

which lead to DISRUPTION of CARTILAGE MICROSTRUCTURE

A
  • INTERFACIAL WEAR
    Adhesion, Abrasion
  • FATIGUE WEAR
    increase strain rate, microtrauma exceed, reparative process
  • HIGH IMPACT LOADING WEAR
    increase Stress, Increase Strain
52
Q

CHANGES in articular cartilage with WEAR:

A
  • LOOSENING of COLLAGEN NETWORK
  • PROTEOGLYCAN EXPANSION (collagen not holding it together)
  • TISSUE SWELLING
  • REDUCED STIFFNESS of cartilage
  • INCREASED PERMEABILITY

-> abnormal:
STRESSED & STRAINS
Mechanoelectrochemical stimuli
ECM REMODELLING of CHONDROCYTES

53
Q

what do the CHANGES in articular cartilage with WEAR eventually lead to

A

OSTEOARTHIRITIS

54
Q

what is an EARLY INDICATOR of OSTEOARTHIRITIS

A

LOSS of PROTEOGLYCANS

Formation of clusters of activated and proliferating chondrocytes is a hallmark
in the early phase of OA cartilage

55
Q

OA:
what do CHONDROCYTES SECRETE that cause ARTICULAR CARTILAGE to be LOST
what do they do

A

METZINCINS:
MMPs & ADAMTSs

ENZYMES that BREAK DOWN (/regulate) ECM

56
Q

MMPs and ADAMTSs are part of which ENZYME FAMILY

A

METZINCINS

57
Q

how many TYPES of MMPs and ADAMTSs are there

A

23 TYPES of MMPs
20 TYPES of ADAMTSs

(19 types ADAMs)

58
Q

OA:
what ENZYME causes CLEAVAGE of COLLAGEN TYPE II
(cleavage removes the collagen)

A

CATHEPSIN K

  • a lysosomal CYSTEIN PROTEASE

(involved in bone remodelling and resorption)

59
Q

OA:
what do MMPs and ADAMTSs do to AGGRECAN (proteoglycan)

A

CLEAVE aggrecan

(Aggrecanases - break down aggrecan)

60
Q

OA:
what results from CLEAVAGE of AGGRECAN by MMPs and ADAMTSs

A

AGGRECAN (proteoglycan) is LINKED to GLYCOSAMINOGLYCANS:
- HYALURONAN (HA)
- KERATAN SULFATE
- CHONDROITIN SULFATE

these sugars are RELEASED and escape

CAUSING SWELLING

61
Q

how does ARTICULAR CARTILAGE WITHSTAND LOAD

A

by ATTRACTING WATER into the NEGATIVELY CHARGED PROTEOGLYCANS

Musculoskeletal System (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions